valve issues/ head issues 1986 720 frankenstien engine.

[napsZ]

well.....i figured it out. the people who sent me the head went out of business. for a good reason. that knocking sound was the valve seats in cylinder #1 falling out and bouncing around. so anyway. i am now doing a turbo ka24de swap and i will drive ol sad panda around until i have the engine and parts built.

[napsZ]

got tired of the head and swapped back. rebuilt the old head and its running great! weber 32 36 is letting this engine rev to 6k i have 18 degrees of advance of 88 octane and i'm not having any issues whatso ever with knocking. i do have a vacuum leak but  i figure as much that will be dealt with in time. i will be pulling the z20 head apart to figure out what was making such a racket. me thinks cam shaft or cam journal. i'll blue print it and share my findings.

[Stoffregen Motorsports]

KA24DE pistons are not used in L/Z hybrid builds.

That is actually my piston of choice when building a 2200 long rod motor, which is my favorite motor on the planet by the way.  You can't cut enough off a 12 valve piston to get the right compression when running a closed chamber head, but the DE piston has that nice dish in it.

[napsZ]

 yup figured out what was the problem. these are .1" divots in the rocker arms. explains the horrific ticking and why this company no longer exists.https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-xpa1/v/t1.0-9/1393923_10203367986978827_7506851593055083673_n.jpg?oh=90642fbf8cec8b6ab516610de24c8882&oe=5465941D&__gda__=1416454519_57dc8738fb0c04668df62292bdbaa1e7

 

[datzenmike]

If those are stock Z series rockers then what oil were you using? Most of today's oils are too low on ZDDP

[napsZ]

i use cheapo break in oil with zinc additive. it started tapping the instant it fired up.

[napsZ]

i have rebuilt the head and solved all of its issues. i have the stock head back on and its runing like a top. the high compression head is going back on in a few weeks when i have my high compression crx back up to helena. "need some form of a daily". i will be dialing back some of my extras i will use the stock z20 cam and just do the head swap for now "intake carb and headers as bolt ons"
  i'm only looking for 200 hp or there abouts with this build on 91 pump gas.i weighed the truck at 2500 pounds so 160 hp per ton should be a perfectly acceptable daily rat truck. i even have passanger seat and a radio. so poiled.

[datzenmike]

200hp from a NAPS head is... ambitious.

 

How did you trim your 720 down to less than a 620????

[napsZ]

no bumpers, new exhaust, no ac,stripped interior, no camper shell, lightweight seats, new radiator,new wheels new tires, leaf springs and no spare.

[napsZ]

with me in it and carpets its about 2700

[napsZ]

its been a long time. and i do apologize. BUT!! here is the update on my Frankenstein project!
the cam shaft disolved in my napz20 head and destroyed the rocker arms. i rebuilt the head and got new rocker arms.

next i installed a comp cams 260 camshaft and a weber 38/38 outlaw carburetor.

so it has a cam, high compression, and a big carb.

and i just finished installing a 53mm turbocharger and it runs like a champ! 8 psi of boost and she screams through the gears.

[napsZ]

[datzenmike]

Run a cold air intake from in front of the rad. This will lower the heat content in the intake air. When compressed, air gets hot enough to self ignite the fuel and is called pre ignition and will destroy an engine before you can let off the gas. The cooler the air the more you can compress it without worry.

 

Maybe an inter cooler in front of the rad. Compressed air concentrates the heat contained in it. The inter cooler sheds this heat, again lowering the intake air temperature.

 

Oil cooler. Prevents heat spikes from boosting. Turbos are so hot they will coke or break down oil. They need lots of cool lubricating oil.

 

KA24E or DE oil pumps from Hardbodys have larger internal rotors and can move more oil. Great for engines that need more oil for a turbo. 

 

A water alcohol injection kit to cool the intake air by absorbing heat by alcohol evaporation.

[napsZ]

i already have a oil pump from a  k engine :) and as for pre ignition or knock i have been paying special attention to the air fuel ratio and dropping ignition advance as needed, along with a set of colder plugs. if i do end up inter-cooling this pig i'll prolly go with a water to air with a recirculating pump. " i just don't like the way an air to air looks jutting out of the front of this truck". i'm running low enough boost that most of these concerns should be fairly low threats. my biggest worry is oil leaks as these are cork sealed engines. even though i did redesign the entire pcv system with parts from work "i'm a mechanic for a Honda dealership". for now i'm going to drive it and tinker until i find something that is causing an actual problem.

[datzenmike]

Ha ha I assumed the usual... that boost leads to more boost to more boost. There have been lots of factory turbos and all are 5-8 PSI and live forever on a pretty much stock carb and pistons. An inter cooler doesn't do much good there.

[napsZ]

i built the engine just to be a smart ass anyway lol the right thing to do is just swap a ka24de in or sr20. but too many people told me not to do this so i'm keeping it ^_^ i only know of two people with a turbo napz. but this also opens up a huge amount of other cars i can play with cause this is a stock weber 38." i do need to rejet it cause it goes lean at the higher rpms. and i dont like lean.

[datzenmike]

That's the trouble with a synchronous carb. A progressive or vacuum secondary you can jet the second barrel much richer so it's only used at max boost.

[napsZ]

i dont really know of any resources on how to jet a weber 38 for boost. i kinda figured boost would be the best possible case for a carb. "everything else i do is fuel injection you just dont see carbs any where else." i'm playing around but i will most likely figure out napz dont like making power..... and swap in a ka24e and turbocharge that. seeing as the headers match up.